The project is designed to examine the equivalence of visual and auditory pattern perception in the adult observer and to assess its development in the child. Patterns are generated and then translated into auditory tone sequences and several visual pattern formats: polygons, line drawings, dot arrays. With patterns generated to form classes, the effects of input format and modality on level of pattern processing have been examined. Processing strategies appear common across modalities and formats, thought perceptual accuracy varies with pattern format. Perceived similarity has been found to be equivalent for polygons, line drawings, and note sequences as representations of common underlying patterns. Class rule learning has been found to transfer from vision to audition. Large individual differences have been noted in the auditory performance of both adults and children. These individual differences will be examined systematically employing special subject populations, e.g. the blind. Investigations of format effects and intermodal transfer will also be extended to elementary school-aged children. The ability of the adult observer to use simultaneously presented visual and auditory pattern information is also to be explored. The question of whether pattern class prototypes serve as efficient codes for visual and auditory pattern memory will be examined.